1. Field of the Invention
The present invention relates to a method of manufacturing airtight vessel whose inside is to be kept airtight, and more particularly to a method of manufacturing airtight vessel which can be suitably applied to display panels of image displaying apparatus. The invention also relates to an image displaying apparatus, and a method of manufacturing image displaying apparatus. It also relates to a method of manufacturing television sets.
2. Related Background Art
Usually, an image displaying apparatus utilizing electron emission requires an envelope for maintaining a vacuum ambience, an electron source provided with a plurality of electron-emitting devices and a drive circuit therefor, an image-forming member having a phosphor or the like which is caused to emit light by the collision of electrons, and accelerating electrodes for accelerating the motions of electrons towards the image-forming member and a voltage source or the like therefor. An image displaying apparatus using a flat envelope, such as a thin image displaying apparatus or the like, may use supports (spacers) as structures to endure the atmospheric pressure.
Two types of the electron-emitting devices are already known, including hot cathode devices and cold cathode devices. Of these two types, known cold cathode devices include field-emission electron-emitting devices (hereinafter abbreviated to the FE type), metal/insulator/metal type electron-emitting devices (hereinafter abbreviated to the MIM type) and surface conduction electron-emitting devices.
FIG. 10 schematically shows the configuration of an example of display panel of an image displaying apparatus using conventional surface conduction electron-emitting devices.
In FIG. 10, reference numeral 103 denotes a rear plate; 104, an external frame and 110, a face plate. The rear plate 103, the external frame 104 and the face plate 110 constitute an envelope (airtight vessel) for keeping the inside of the display panel vacuum. An electron source substrate 101 is fixed to the rear plate 103, and N×M surface conduction electron-emitting devices 106 are formed over the electron source substrate 101 (N and M are positive integers not smaller than 2, whose number is appropriately set according to the intended number of display pixels). The N×M electron-emitting devices 106 are wired with M X-directional wires 102 and N Y-directional wires 105 as shown in FIG. 10. Between the X-directional wires 102 and the Y-directional wires 105, at least where they cross, an insulating layer (not shown) is formed to maintain electric insulation.
A fluorescent film 108 consisting of phosphors is formed over the under face of the face plate 110, differentiated in color by phosphors (not shown) of three primary colors including red (R), green (G) and blue (B). Black components (not shown) are provided between the phosphors of different colors constituting the fluorescent film 108, and a metal back 107 consisting of Al or the like is formed on the face of the fluorescent film 108 toward the rear plate 103.
Dx1 through Dxm, Dy1 through Dyn and a high voltage terminal Hv are airtight-structured terminals for electrical connection, provided to electrically connect the display panel to an electrical circuit (not shown). Dx1 through Dxm are electrically connected to the X-directional wires 102 of the electron source, Dy1 through Dyn to the Y-directional wires 105 of the electron source, and Hv to the metal back 107.
The inside of the envelope 111 is maintained in a vacuum of around 1.3×10−4 Pa. As the display area of the image displaying apparatus expands, the need increases for means to prevent deformation or destruction of the rear plate 103 and the face plate 110 due to the pressure difference between the inside and the outside of the envelope 111. Increasing the thicknesses of the rear plate 103 and the face plate 110 would not only make the image displaying apparatus heavier but also give rise to image distortion and parallax when the display panel is viewed obliquely. In view of this problem, the configuration shown in FIG. 10 is provided with structural supports (known as spacers or ribs) 112 consisting of relatively thin glass plates and intended to stand the atmospheric pressure. In this way the gap between the substrate 101 on which electron source is formed and the face plate 110 on which the fluorescent film 108 is formed is usually kept between sub-millimeters to a few millimeters, and the inside of the envelope 111 is kept at a high degree of vacuum.
In an image displaying apparatus using the display panel, when voltages are applied to the electron-emitting devices 106 through extra-container terminals Dx1 through Dxm and Dy1 through Dyn, electrons are emitted from each of the electron-emitting devices 106. At the same time, a high voltage of hundreds to thousands of volts is applied to the metal back 107 via the extra-container terminal Hv to accelerate the motions of the emitted electrons and cause them to collide against the inner face of the face plate 110. The phosphors of different colors constituting the fluorescent film 108 are thereby excited to emit light and display an image.
In addition to ones of the configuration described above, there also are other displays, such as liquid crystal displays, plasma displays and EL displays, in which the internal space is defined by a frame, a face plate and a rear plate, the latter two being two members opposite each other, and a desired atmosphere is maintained in the internal space.
Examples of the prior art realizing such displays are disclosed in Patent Documents 1 and 2.
Patent Document 1: U.S. Pat. No. 5,813,893
Patent Document 2: Japanese Patent Application Laid-Open No. 11-135018